Can you see the northern lights in Great Falls in July?

On dark, clear nights with enough activity. 31 of 31 nights at Great Falls have civil darkness, and 3% of past July days reached Kp 6.

How dark is Great Falls in July?

Great Falls averages 7.1 hours of civil night a night in July 2027, from 6 h 38 min on the 1st to 7 h 43 min on the last night.

How cloudy is Great Falls in July?

NASA POWER's 2001 to 2020 climatology gives Great Falls's 1 degree cell 38% mean cloud in July, against 62% for the whole year. It is an all-hours average, not a forecast.

What is the best night in July 2027 for aurora in Great Falls?

By darkness and moon alone, Jul 29, with 4 h of moon-free darkness inside 10 PM to 2 AM at Great Falls. Activity on that date will only be known hours ahead.

Is July or August better in Great Falls?

By civil night times the clear share, July scores 4.3 hours at Great Falls and August 4.8. August comes out ahead.

Great Falls · July 2027

Northern lights in Great Falls in July 2027

Answer

July gives Great Falls 7.0 hours of civil night on the 15th, the 11th darkest of its 12 months, under 38% mean cloud. 3% of July days since 1996 reached Kp 6, enough for the oval edge to reach Great Falls.

7.1 h

civil night, average night

SunCalc for 47.50, -111.30; NASA POWER; GFZ Kp

July against the rest of the year

4.1

3.8

3.2

2.8

2.6

2.8

4.3

4.8

4.9

4.4

4.2

4.4

July cloud at Great Falls averages 38% in NASA POWER's 2001 to 2020 record, 24 points clearer than its yearly mean. No month at Great Falls is clearer. By civil night times clear sky, July scores 4.3 hours at Great Falls, 5th of 12. Lethbridge, 269 km away, averages 42%, cloudier by 4 points.

Civil night at Great Falls starts July at 6 h 38 min and reaches 7 h 43 min by July 31 as the nights lengthen by 1.1 hours. The 10 PM to 2 AM window is fully dark on 17 of 31 nights. True astronomical darkness, the sun 18 degrees down, lasts 2.9 hours on the 15th.

July night by night

July opens toward a new moon on Jul 3, with full moon on Jul 18, in America/Denver dates. Great Falls gets 105 hours of civil night with the moon below the horizon across the month. The best of them for moon-free darkness inside 10 PM to 2 AM: Jul 29 (4 h), Jul 30 (4 h), Jul 31 (4 h).

1
5% lit
5.3 h
2
1% lit
6.5 h
3
0% lit
6.7 h
New
4
2% lit
6.6 h
5
7% lit
6.1 h
6
14% lit
5.7 h
7
23% lit
5.4 h
8
34% lit
5.1 h
9
44% lit
4.8 h
10
55% lit
4.5 h
11
65% lit
4.2 h
12
75% lit
3.7 h
13
83% lit
3.1 h
14
90% lit
2.5 h
15
95% lit
1.6 h
16
98% lit
0.6 h
17
100% lit
0.0 h
18
100% lit
0.0 h
Full
19
98% lit
0.0 h
20
94% lit
0.3 h
21
89% lit
0.6 h
22
82% lit
0.9 h
23
74% lit
1.2 h
24
65% lit
1.5 h
25
55% lit
1.8 h
26
44% lit
2.2 h
27
34% lit
2.8 h
28
24% lit
3.5 h
29
14% lit
4.5 h
30
7% lit
5.8 h
31
2% lit
7.2 h

Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.

Activity in past Julys

Great Falls needs Kp 6 for the average oval edge to sit overhead. 26 of the 930 July days from 1996 to 2025 (3%) reached it in the GFZ Potsdam record, 9th of 12 months; storm days with Kp 5 or more made up 9%. Great Falls sits at 54.3 degrees geomagnetic. The lowest NOAA storm level whose typical viewing latitude reaches it is G3 (Kp = 7). By SWPC's rule the average oval edge is overhead only at Kp 6.

July across United States

Great Falls ranks 6th in United States for civil night on July 15, behind Buffalo at 7.8 hours. Coming from June (6.6 hours at Great Falls), July adds darkness, and the nights keep growing into August (8.5 hours on the 15th).

Civil night on July 15 and July cloud, month-page towns in United States
Town	Civil night	Cloud
Buffalo	7.8 h	56%
Portland, Maine	7.6 h	55%
Minneapolis	7.4 h	46%
Duluth	7.2 h	51%
Fargo	7.1 h	48%
Great Falls	7.0 h	38%
Seattle	7.0 h	47%
Juneau	4.1 h	81%
Anchorage	2.1 h	83%
Eagle River	2.0 h	83%
Fairbanks	0.0 h	77%

Darkness and moon, every night

Great Falls, July 2027: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Thu Jul 1	6 h 38 min	1 h 44 min	5 h 21 min	3 h 50 min	5%
Fri Jul 2	6 h 39 min	1 h 48 min	6 h 28 min	3 h 50 min	1%
Sat Jul 3	6 h 40 min	1 h 53 min	6 h 40 min	3 h 51 min	0%
Sun Jul 4	6 h 42 min	1 h 57 min	6 h 37 min	3 h 46 min	2%
Mon Jul 5	6 h 43 min	2 h 1 min	6 h 7 min	3 h 15 min	7%
Tue Jul 6	6 h 45 min	2 h 6 min	5 h 43 min	2 h 51 min	14%
Wed Jul 7	6 h 46 min	2 h 11 min	5 h 24 min	2 h 30 min	23%
Thu Jul 8	6 h 48 min	2 h 16 min	5 h 6 min	2 h 12 min	34%
Fri Jul 9	6 h 49 min	2 h 20 min	4 h 49 min	1 h 53 min	44%
Sat Jul 10	6 h 51 min	2 h 25 min	4 h 30 min	1 h 34 min	55%
Sun Jul 11	6 h 53 min	2 h 30 min	4 h 9 min	1 h 11 min	65%
Mon Jul 12	6 h 55 min	2 h 36 min	3 h 42 min	44 min	75%
Tue Jul 13	6 h 57 min	2 h 41 min	3 h 9 min	10 min	83%
Wed Jul 14	6 h 59 min	2 h 46 min	2 h 28 min	0 min	90%
Thu Jul 15	7 h 1 min	2 h 51 min	1 h 36 min	0 min	95%
Fri Jul 16	7 h 3 min	2 h 56 min	37 min	0 min	98%
Sat Jul 17	7 h 6 min	3 h 1 min	0 min	0 min	100%
Sun Jul 18	7 h 8 min	3 h 7 min	0 min	0 min	100%
Mon Jul 19	7 h 10 min	3 h 12 min	0 min	0 min	98%
Tue Jul 20	7 h 13 min	3 h 17 min	20 min	15 min	94%
Wed Jul 21	7 h 15 min	3 h 23 min	37 min	31 min	89%
Thu Jul 22	7 h 18 min	3 h 28 min	54 min	47 min	82%
Fri Jul 23	7 h 21 min	3 h 33 min	1 h 10 min	1 h 2 min	74%
Sat Jul 24	7 h 23 min	3 h 38 min	1 h 28 min	1 h 18 min	65%
Sun Jul 25	7 h 26 min	3 h 44 min	1 h 49 min	1 h 38 min	55%
Mon Jul 26	7 h 29 min	3 h 49 min	2 h 14 min	2 h 2 min	44%
Tue Jul 27	7 h 32 min	3 h 54 min	2 h 47 min	2 h 33 min	34%
Wed Jul 28	7 h 34 min	3 h 59 min	3 h 31 min	3 h 16 min	24%
Thu Jul 29	7 h 37 min	4 h 5 min	4 h 31 min	4 h	14%
Fri Jul 30	7 h 40 min	4 h 10 min	5 h 46 min	4 h	7%
Sat Jul 31	7 h 43 min	4 h 15 min	7 h 12 min	4 h	2%

Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Great Falls in July?: On dark, clear nights with enough activity. 31 of 31 nights at Great Falls have civil darkness, and 3% of past July days reached Kp 6.
How dark is Great Falls in July?: Great Falls averages 7.1 hours of civil night a night in July 2027, from 6 h 38 min on the 1st to 7 h 43 min on the last night.
How cloudy is Great Falls in July?: NASA POWER's 2001 to 2020 climatology gives Great Falls's 1 degree cell 38% mean cloud in July, against 62% for the whole year. It is an all-hours average, not a forecast.
What is the best night in July 2027 for aurora in Great Falls?: By darkness and moon alone, Jul 29, with 4 h of moon-free darkness inside 10 PM to 2 AM at Great Falls. Activity on that date will only be known hours ahead.
Is July or August better in Great Falls?: By civil night times the clear share, July scores 4.3 hours at Great Falls and August 4.8. August comes out ahead.

Sources and verification

SunCalchttps://github.com/mourner/suncalc
NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
GFZ Potsdam Kp indexhttps://kp.gfz.de/en/data
NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora

Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.